This invention relates to optical fibers and more particularly to an optical fiber coupler of the beam splitter type.
Copending patent application Ser. No. 074,923, filed Sept. 13, 1979 and Ser. No. 117,425, filed Feb. 1, 1980, of the instant inventor, whose disclosures are incorporated herein by reference, each disclose a different embodiment of an optical fiber coupler of the beam splitter type employing a reflective surface at the interface between two abutting single core optical fibers with the interface being angled 45.degree. with respect to the longitudinal axis of the two abutting optical fibers to provide the desired three port optical fiber coupler of the beam splitter type.
Optical fiber couplers for concentric core optical fibers have in the past used very small diameter optical fibers. For instance, two such fibers on the transmitter end and a bundle of such fibers on the receiver end with the optical fiber on the central core separated out from the bundle of optical fibers before going to utilization means, such as, a light detector or a third branch fiber.